About f7params,need help

Now im using cordova +vue+framerwork7 I want to do this when user tap backbutton if current route is 'main' or 'login' notice user that 'if you press backbutton again,app will close' else, do router back f7params:pushstate may help me,but i still dont know how to Achieve the second effect

so can anyone help to explain the meaning of params in f7params and how to configure them

List of all params available in docs http://framework7.io/docs/app.html#app-parameters

but it doesnt solve my problem maybe i havent described it clearly

i am using f7-vue
when i press backbutton. i dont want to change url. just want to route back but when I set property 'pushState',it doesnt work
i tried like this

also this

and f7-vue docs does not show how to set It

Don’t use pushState in cordova app! You can handle Android’s back button separately:

$$(document).on('backbutton', function (e) {
  // do something what you need on back button clicked